(a) Field of the Invention
This invention relates to the cleaning of large storage tanks, and more particularly, but not by way of limitation, to the cleaning of a bulk oil storage tank and removing sediments from the bottom of the tank.
(b) Discussion of Prior Art
Heretofore, large bulk oil storage tanks, ranging in size from 400 to 40,000 plus barrels of crude oil, have been cleaned periodically to check the integrity of the tank structure and maintain usable capacity of the tank by removing sediments from the crude oil, such as sand, clay, water, heavy oil and sludge. Also the build up of the sediments in the tank can plug an oil discharge line, when oil is pumped out of the tank to be delivered to an oil refinery.
Currently during the bulk tank cleaning process, one or two workmen enter the inside of the large tank through a removable, manway door in the side of the tank. At this time, high pressure water is introduced through a water jet pipe or a water cannon into the sediment creating a water and sediment slurry. The water and sediment slurry is then vacuumed into a vacuum truck tank and carried to a disposal site. Inside the tank and during the mixing of the high pressure water with the sediment to create a water and sediment slurry, dangerous gases occur. The breathing of these gases can easily cause illness or death to the workman who fails to wear a self-contained breathing apparatus, provided by an oil tank, safety consultant. Because of the added expense, oil and gas companies may or may not hire the safety consultant with the required breathing equipment for their workmen.
The subject no-entry, tank cleaning system eliminates the need for one or two workmen to enter the inside of the storage tank and risk breathing dangerous gases. Also, the cleaning system eliminates the high cost of added water delivery trucks, an added water pressure pumping truck and having to hire the air safety consultant with air safety equipment.